1. Field of the invention
This invention relates to a cleaning agent for removing foulings such as fats and oils adhering to metal parts, etc. and fluxes and fingerprints adhering to electronic parts, etc., and a cleaning method.
2. Description of the Prior Art
Freon solvents or halogenous solvents have been used for degreasing and cleaning matter to be cleaned such as metal parts, electronic parts, semiconductor parts, etc., chiefly because they are noncombustible and free of danger of ignition, and excellent in detergency. However, in recent years, under concern over the problem of destruction of the earth environment and influence on human bodies, conversion to aqueous cleaning agents containing surface active agents or alkalis as main components, hydrocarbonic cleaning agents, alcoholic cleaning agents, or quasi-aqueous cleaning agents wherein the third petroleum hydrocarbons are dispersed in water using surface active agents is being made.
However, in the case of cleaning methods using aqueous cleaning agents, there are problems that the cleaning agents have too high foamability, are insufficient in detergency, and corrode matter to be cleaned, and a large amount of waste water must be treated, and so on. Both hydrocarbonic cleaning agents and alcoholic cleaning agents are combustible, have high inflammability, and have the danger of ignition. Further, the quasi-aqueous cleaning agents have drawbacks that when phase separation takes place they have inflammability, nonuniformity arises in detergency, and a large amount of waste water must be treated, and so on.
A cleaning agent containing an alkylene glycol monophenyl ether, a glycol ether solvent and a surface active agent as main components is proposed in Japanese Laid-Open Patent Publication No. 51599/1993. However, this cleaning agent does not have sufficient detergency, and there is the possibility that since it contains nonvolatile components, they remain in the matter to be cleaned and have an influence thereon. Further, the growth and reproduction of organisms are influenced by ethylene glycol alkyl ether compounds, and their permissible concentrations are being strictly restricted, and the use thereof is not desirable.
Japanese Laid-Open Patent Publication No. 9498/1993 discloses a cleaning method comprising using composition which comprises a compound represented by the following formula EQU R--O--A.sub.n --COCH.sub.3 or EQU R--O--A.sub.n --R
wherein R is a hydrogen atom or a lower alkyl group, A is an ethoxy or propoxy group, and n is 1 or 2,
and water. However, specifically, a cleaning method is disclosed wherein as specific compounds to be used, compounds which dissolve in water at certain temperatures or more, but do not dissolve in water at temperatures lower than the certain temperatures, such as acetates, from propylene glycol monomethyl ether acetate down, and ethylene glycol diethyl ether are used, and their solubility dependent on temperature is utilized.
Therefore, there still exists a need for the provision of a cleaning agent which is rich in detergency on oily matter adhering to matter to be cleaned, easy to handle because there is no need of using it under specified temperatures, and further, safer from an ecological viewpoint.